Regulator for dynamo-electric machines



(No Model.)

E. THOMSON. REGULATOR FOR DYNAMO BLECTRIU MAGHINES No. 509,499.'Patented Nov. 28, 1893.

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NrrnoS'rA'rns ATENT FFTQEQ ELIHU THOMSON, OF SVVAMPSCOTT, MASSACHUSETTS,ASSIGNOR TO THE THOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

REGULATOR FOR DYNAlVlO-ELECTRlC MACHINES.

SPECIFICATION forming part of Letters Patent No. 509,499, dated November28, 1893. Application filed April 11, 1892. Serial No. 428,708- (Nomodel.)

To aZZ whom it may concern.-

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampscott, in the county of Esssex and State ofMassachusetts, have invented certain new and useful Improvements inDynamo-Electric Machines, of which the following is a specification.

The present invention relates to an improvement in that class of dynamoelectric machines whether generators or motors which are compound wound,and which consequently have a portion of their field magnet ismfurnished by a shunt across the mains, or by a separate exciter kept ata fairly constant potential, while the remaining portion of their fieldmagnetism is due to the main current passing through a second set offield coils, generally known as series coils.

My invention is designed to adapt such machines to the conditionsincident to their working in multiple arc, and at the same time toprovide for the relative adjustment of the magnetic effects due to theseries coils of the different machines, so that each one may be kept atsuch potential as to take its proper proportion of the load. Theadjustment of the series field is also made for the purpose of adaptingthe electromotive force of the machines to variations in drop ofpotential, so that under light load they may give a certain potential,and under heavy loads may increase the potential by what is known asover-compounding or compounding for increase of potential at theterminals, or for constant potential at a distant point. Two or moresuch machines when running in multiple arc and feeding the same systemof mains, should be provided for stability of action, with an equalizingconnection between those points in their circuits at which their seriesfield terminals are connected to the commutator brushes. Now withmachines thus working in multiple arc and connected by an equalizertheir series field coils are practically in multiple are, and if a shuntbe thrown around one of them,such ashunt will act equally to divertcurrent from all the other field coils connected in the system. It doesnot, in other words, individualize its shunting effect to the particularmachine for which it is intended. Evidently then, no proper adjustmentof the relation to each other of the series windings of the differentmachines can be obtained under the condition mentioned. To avoid thiscliificulty is the aim of the present invention. The series turns ofsuch machines as are running in multiple are are divided into two ormore sections, part of which are always in the main circuit and are notvaried by shunting, While around the remainder a variable shunt isprovided, whereby in each machine the total influence of the differentsections of the series coil may be varied bya proper variation of onesuch section. It is evident that in this way anindividualadjustmentmaybeobtained which, while not absolute, may be madeapproximately correct,and the proper balance of work between themachines may be preserved by adjusting the relative effects of theirseries windings.

In the accompanying drawings illustrating the invention, Figure 1 showsa dynamo electric machine wound after the present invention. Fig. 2shows diagrammatically two machines similarly wound, and coupled up soas to work in multiple are on a common circuit, and Fig. 3 shows asingle machine by itself similarly constructed.

The machine shown in Fig. 1 has four poles which are energized by shuntor separate exciting coils S, and in addition by coils D D, E E, throughwhich the main current passes, and which are the series coils forcompounding. Variable resistances R R are put in shunt around the coilsE E, while the coils D D are left unshunted and traversed by the maincurrent in toto. Of course however, these coils may be shunted by apermanent shunt at any time when the number of ampere turns in D Dbecomes too great for the existing condition of the circuit.

Referring now to Fig. 2, two armatures A, A are shown with shunt fieldmagnet coils S, S which, as stated before, may be replaced by separateexciting coils furnishing an initial field. In series with the armaturesare heavy series coils divided into sections D',E for the one machine,and D E for the other. The sections D, D are connected directly to themain M, and are never shunted. Around the sections E, E respectively arevariable resistance shunts R, R whereby such sections maybe more or lesscompletely shunted and the desired adjustment of the machinesindividually and relatively to one anotherbe effected. The equalizingconnection is shown at O. The variable resistances may be of any desiredtype. They may in fact be shunts of definite Value connected across thesections E, E such as strips of German silver shunting from five tofifteen or twenty per cent. of the current, one strip being removed andre placed by another as becomes necessary to give the desired effect.

In Fig. 3 a single machine .A is shown diagrammatically which has itsfield excited by a shunt coil S and a series coil divided into sectionsD and E. The section E is shunted by a variable resistance R, andrenders the effect of the series coil variable.

The operation of the invention will be understood from the foregoing.Evidently if the shunting resistance spanned the entire series coil itwould not only divert current from the coil of that particular machine,but also would shunt substantially the same amount of current around thecorresponding coils of such other machines as might be running inmultiple therewith,for the resistance of the equalizing connection isvery low. The field of each machine would therefore be correspondinglyaffected. Vhen only a portion of the series coil is shunted, as hereindescribed, the relative effect of the series coils upon the differentmachines may be regulated, for any influence which a change ofresistance R or R has upon a companion machine is comparatively small,and maybe rendered unimportant.

Myinvention is especially important when using machines in which thecharcteristic curve, or curve of compounding, is different for thedifferent machines. In such case the machines might run togetherperfectly at half load but at full load one machine would be found to becarrying more than its due share of current. This condition of affairsshould be rectified by lowering the potential of that machine which isdoing the greater part of the work, and this may be done by simplyadjusting the series field strength accordingly.

What I claim as new, and desire to secure by Letters Patent, is-

1. The combination of two or more compound wound dynamo electricmachines working in multiple arc and connected by an equalizer, withmeans for adjusting individually, and with relation to one another thefield strength of the different machines due to their respective serieswindings, as set forth.

2. The combination of two or more compound wound dynamo electricmachines workin g in multiple arc and connected by an equalizer, withmeans for shunting portions of the series windings of such machinesindividually, and thereby altering the relation between their respectiveseries fields, as required.

3. The combination of two or more compound wound dynamo electricmachines working in multiple arc and connected by an equalizer, andhaving their series windings divided respectively into sections, part ofwhich are always in the main circuit of the machines, and another partof which are shunted by shunt connections of variable resistance.

4. The combination of two or more compound wound dynamo electricmachines working in multiple arc, and means for shunting portions of theseries windings in such machines and thereby altering the relationbetween their respective series fields, as required.

5. A com pound wound dynamo electric machine having its series windingdivided into sections, and a shunt connection of variable resistancearound a part only of such series winding, as set forth.

In witness whereof I have hereunto set my hand this 5th day of April,1892.

ELIIIU THOMSON.

\Vitnesses:

J ornv W. GIBBONEY, BENJAMIN B. HULL.

